This book constitutes the refereed proceedings of the 6th International Conference on Conceptual Structures, ICCS'98, held in Montpellier, France, in August 1998.
The 20 revised full papers and 10 research reports presented were carefully selected from a total of 66 submissions; also included are three invited contributions. The volume is divided in topical sections on knowledge representation and knowledge engineering, tools, conceptual graphs and other models, relationships with logics, algorithms and complexity, natural language processing, and applications.

The 13th International Conference on Conceptual Structures (ICCS 2005) was held in Kassel, Germany, during July 17 22, 2005. Information about the c- ference can be found athttp: //www.kde.cs.uni-kassel.de/conf/iccs05. The title of this year s conference, Common Semantics for Sharing Kno- edge, waschosentoemphasizeontheonehandtheoverallaimofanyknowledge representationformalism, to support the sharing of knowledge, and on the other hand the importance of a common semantics to avoiddistortion of the meaning. We understand that both aspects are of equal importance for a successful future of the...